Bio-polysaccharide composites mediated degradation of polyaromatic hydrocarbons in a sandy soil using free and immobilized consortium of Kocuria rosea and Aspergillus sydowii

• Published in: Environmental science and pollution research international 2022-11, Vol.29 (53), p.80005-80020
• Main Authors: Khandelwal, Ashish, Sugavanam, Ramya, Ramakrishnan, Balasubramanian, Dutta, Anirban, Varghese, Eldho, Banerjee, Tirthankar, Nain, Lata, Singh, Shashi Bala, Singh, Neera
• Format: Article
• Language: English
• Subjects: Alginates; Alginic acid; Anthracene; Anthracenes; Aquatic Pollution; Aspergillus sydowii; Atmospheric Protection/Air Quality Control/Air Pollution; Bentonite; Biodegradation, Environmental; Carboxymethyl cellulose; Carboxymethylcellulose; Carboxymethylcellulose Sodium; Cell culture; Cellulose; Consortia; Correlation coefficient; Correlation coefficients; Degradation; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fluorene; Fluorenes; Formulations; Guar gum; Half-life; High performance liquid chromatography; Hydrocarbons; Inoculation; Kocuria; Liquid chromatography; Loam soils; Microorganisms; Nano-bioremediation Approaches for Sustainable Agriculture; Naphthalene; Naphthalenes; Nitrogen; Phenanthrene; Phenanthrenes; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - metabolism; Polysaccharides; Pyrene; Pyrenes; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sand; Sandy loam; Sandy soils; Soil; Soil degradation; Soil Microbiology; Soil Pollutants - metabolism; Waste Water Technology; Water; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-022-19252-5

Based on our previous study in minimal medium, Kocuria rosea and Aspergillus sydowii were identified as the best microbes for degradation of mixture of polyaromatic hydrocarbons (PAHs). The present study reports PAH degradation potential of these microbes in free and immobilized form. PAHs were extracted using QuEChERS-mediated process followed by quantification by high performance liquid chromatography. The microbial consortium of Kocuria rosea  +  Aspergillus sydowii was formulated in three bio-formulations, namely (i) bentonite-alginate composite beads; (ii) water dispersible granule composite using guar gum-nanobentonite; and (iii) composites of carboxymethyl cellulose-bentonite and were applied in PAH fortified (100 µg g −1 ) sandy loam soil. Results suggested that degradation data fitted well to first order kinetics as in most of the cases, the values of correlation coefficient (r) were > 0.95. The half-life (t 1/2 ) values for PAHs in the uninoculated control soil were: naphthalene (10.43 d), fluorene (22.43 d), phenanthrene (24.64 d), anthracene (38.47 d), and pyrene (34.34 d). Inoculation of soil with free culture microbial consortium (without or with nutrient) and bio-formulation of degrading cultures enhanced degradation of all PAHs and half-life values were significantly reduced for each PAH: naphthalene (1.76–2.00 d), fluorene (2.52–6.65 d), phenanthrene (4.61–6.37 d), anthracene (9.01–12.22 d), and pyrene (10.98–15.55 d). Among different bio-formulations, guar gum-nanobentonite-based composite exhibited better efficacy for degradation of naphthalene, fluorene, phenanthrene, anthracene, and pyrene. The addition of microbial consortium in PAH fortified soil increased 16S rRNA gene copies of Alphaproteobacteria and Bacteroidetes , compared to the uninoculated, PAH-fortified control. The microbial functional gene assays showed that the gene copies of amo A, nir K, nir S, and anammox increased, suggesting nitrogen regulation in the PAH-fortified soil.